1. Field of the Invention
The present invention relates to valves and, in particular, to a valve for regulating fluid, such as liquid fuel, and to a fluidic apparatus and a fluid-supplying apparatus each including the valve.
2. Description of the Related Art
In recent years, from the energy-saving and environmental points of view, research and development has been conducted regarding using fuel cell systems as power source units for electronic apparatuses, such as mobile phones and personal computers. In such research and development, the supply of fuel by interposing a micropump between a fuel cartridge and a power-generating cell has been studied.
International Publication No. 2008/007634 discloses a piezoelectric pump in which check valves to prevent the backward flow of fluid are provided at the inlet and the outlet, respectively. However, depending upon the circumstances under which a fuel cell system is driven, the fluid pressure of the fluid flowing from the fuel cartridge into the piezoelectric pump may become high. The piezoelectric pump provided with the check valves prevents the backward flow but cannot prevent the forward flow. Therefore, the piezoelectric pump has a problem in that, if the pressure at the inlet is high, an excessive amount of fuel may be supplied.
In this respect, a valve may be interposed between the fuel cartridge and the pump or on the downstream side of the pump. Known valves intended for such use include electromagnetic and piezoelectric valves in which the valves are driven to be opened and closed by active elements, such as an electromagnetic coil and a piezoelectric element. For example, International Publication No. 2008/081767 discloses a valve including a piezoelectric element as a drive source. However, the active element is susceptible to failure. For example, in the case of the piezoelectric valve, there is a problem in that the piezoelectric element is difficult to handle and cracks and migration may occur.